The present invention relates to a device for applying compressive pressures to a patient's limb.
Blood flow in patient's extremities, particularly the legs, markedly decreases during extended terms of confinement. Such pooling or stasis is particularly acute in surgery and during recovery periods immediately thereafter.
Blood flow compressive devices, such as shown in U.S. Pat. Nos. 4,013,069 and 4,030,488, incorporated herein by reference, develop and facilitate the application of compressive pressures against a patient's limb and in so doing promote venous return. The device comprises a pair of sleeves which are wrapped about the patient's limbs, with a controller for supplying the pressurized fluid to the sleeves. Sleeve devices are disclosed in U.S. Pat. Nos. 4,402,312 and 4,320,746, incorporated herein by reference.
One use for the above mentioned devices is the prevention of deep venous thrombosis (DVT) which sometimes occurs in surgical patients when they are confined to bed. When a DVT occurs, the valves that are located within the veins of the leg can be damaged which in turn can cause stasis and high pressure in the veins of the lower leg. Patients who have this condition often have leg swelling (edema) and tissue breakdown (venous stasis ulcer) in the lower leg.
In the past, the fluid supplied by the controller to the sleeves was controlled by a flow control valve, and it is desirable to provide an improved manner of controlling the pressure supplied to the sleeves.